Headlight befiectoh



`Min-d1 3l, 1925.

c. A. B. HALVORSON, JR L HEADLIGHT REFLECTOR original Filed Jan.

17', 1921A l2 Sheets-Sheet l Mar-ch 31. 1925.

C. A. B. HALVORSON, JR

Hmmm-HT REFLEGTOR an'. 17, 2 sheets-snaai 2 Original Eiled J i is located in the ling surface 12,

make or employ a Mangin mirror with a reliecting surface extended 'to its focal plane, and in order to avoid a gap between the front surface 12 and the Mangin mirror employed, when secured to yeach other. However when it is desired to shift the entire rcliecting surf-aco in back of the focal plane in a 'reflector in 'which a Mangin mirror is employed as an element of the back reflector, the surfaces 12 and 13 are cut through their focal planes .and arranged as above described with reference to Fig. 2, In that case a Mangin mirror is secured to the back surface 13, in a manner similar to that described with reference to the surface 12 in Fig. 3, arranged with its axis Ioincident with the axis 16 of the back surface 123, as shown in Fig. 1.

A suitable source of light is located in the focus of the front reflecting surface 12 indicated at. 15. l preferably employ an incandescent lamp having a concentrated lilamcnt, which may be suitably mounted within the casing in a fixed position as indicated diagrammatically at 15 in Figs. 1 and 2. However, I preferably employ an adjustable light source, movable in the focal plane, as shown in Fig. 3. 1n this arrangement, a bulb 22 is secured in a tubular socket member 23 having a flange 24: at one end. The socket 23 is loosely mounted in a supporting frame 25, which is connterbored at one end to accommodate a helical expansion spring 2G. vThe spring 26 surrounds the socket 23 bearing against the frame 25 at one end and against'the flange 2d: at its opposite end' and normally urges the bulb 22 upwardly toward the frame 25. This upward movement is limited by a cam surfaced stop 27 which is rigidly 'secured to one end of a pin 28 in any suitable manner. The .pin 28 is provided with a screw head 29 at .its opposite end extending out of the casing 10 and is loosely mounted in a sleeve il() so that it. may be rotated about its axis by means of the screw head 29 from outside of the casing. By rotating the pin 28, the cani surface o'l'; thc stop 27 caused to engage the llange 2l and move the socket 23 against thetension of the spring 26. In this manner, the light source may in the focal plane and adjusted to the desired position. 4

Since a point source of ligl'it is not avail able, in order to illustrate the direction of the reliected rays oflight it is convenient to regard the light source indicated-`oy the numeral 1 5 as a point source. As this source focus of the front reflectany rays of light, saythe .rays 31, 31', Which strike this surface are reliccted parallel to its axis le, in accordn ance with Well known laws governing retlection from parabolic surfaces, as indicatedr by the reiected rays '32, 32. lith referbe moved is capable' of meeting the ence to those rays striking the back surface 13, since its focus below the focus of thel front surf coincide, all rays of light from the source 15 striking the back surface are reflected downward.

In accordance with well known laws, rays from a, light source in its focus are from a Mangin mirror parallel to itsa-Xis. Il' the back surface is forme/d entirely of a l''angin mirror as shownin Fig. 3or of a Mangin mirror and a parabolic surface with their axes coincident, as shownin Fig. 1, all reflected 'ays are directed downward. 'lo illustrate, any ray directed upwardly, say the rays 33, apparently come from a point 8l located on its axis 16 in front of the focaly plane, and such rays are therefore directed downward, as indicated b v the. reflected rays 33. Any ray directed downward `from the source say the rays 35, pass through the axis 16 of the back, reflecting surface 13, and apparently come from a point, Soon said axis in back of the focal plane, and such rays are also directed downward, as indicated by the reflected rays 35.

It will thus be seen that inday lamp en1- bodying the present; invention, the light source is located at or substantiallyat '.ihe focus of the front refiecling surface of revolution,'and that the rays which strike this surface are reflected parallel to its axis, and therefore can be used for distant lighting, that is, to produce an illuminated field for a 4considerable distance ahead ofr the reflector and at they same time be substantially nonglaring, inasmuch as the said rays form a concentrated vbeam having a relatively smallangular divergence, which produces distant lighting with permissible or substantially no glare, whereas thev rays which are reliectcd by the surface. otvrevolulion yback of the light source, and towlucli heretofore the disturbing glare was largely due, are, by the non-coincident relation oi'v the axis of said rear reflecting surface to the axisof the front reflecting sul face of revolution, reiiected downward and produce proximate lightii'ig ywithout glare.

In the present instance, thel nocoincident relation of the axes of the front and rear reliecting surfaces of revolution is, a xed relation', which enables an inexpensive and highly 'efficient yheadlight to be made, which requirements of the authbrities as to proper tion' with.k 'respect to glare and to distant lighting,fand which is available at a. minimiuu cost to users of the inexpensive cars.

While I have described my invention as embodied in concrete forms iii accordance road illuminaare 12, and since the focal planes reflected striking the back surface 13,

izo

with the provisions ofthe patent statutes,`

lao

. cations thereof will i suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim as vnew and desire to Secure by Letters Patent of the United States,

l1`."`A"1"'eflectorcomprising two transversely truncated -reflecting surfaces .of revolution secured together with their axes displaced but parallel, and with their focal planes eoincldent.

2. A reflector comprising two transversely truncated reflecting surfaces of revolution secured together one in front of the other with their -axe's displaced but parallel, and with their focal planes coincident, in combination with a source of light in the focus of the surface forming the front part of the reflector.

3. A reflector comprising a parabolic refleeting surface cut into two parts yon a line the part in front of the focus perpendicular to its axis through the focus, a Mhngin mirror fixed in and constituting an element of the art back of the focus, said parts being re atlvelv dis laced lwith the'axis of a Mangin mirror and) the axis of parallel.

p ane and bodl vertically in. relatlon to eac! 'of the front reflecting surface and in the focalplane of the other.

6. In combination, 'a lamp casing, a re- Hector located therein and having a front portion of a reflecting surface of relvolu-I. tion, a li of said ront portion to cause the said portion to projectv a central distant lighting beam, and having another portion of a re-- fleeting-:surface of revolution at the rear of said light source and bodily displaced with relation to the said front portion .with its axis non-coincident with and below. the axis of the said front portion to project its beam of light downward and obtain proximate lighting without glare.

cRoiIwELL A. B.'HALvoRsoN,f'JR.

arran ed on opposite ht source substantially at the focus 4` 

